Posts Tagged: vole
Burrowing Pests in the Garden?
Advice from the Help Desk of the
UC Master Gardener Program of Contra Costa County
Client: Some animal is burrowing throughout my garden. I've had pocket gophers in the past, but I'm not sure that's what I've got this time. Could you help me identify the “burrower” and suggest possible controls? Also, are these pests nocturnal?
MGPCC Help Desk: Thank you for contacting UC Master Gardeners of Contra Costa with your question regarding pest control of the burrowing pest(s) in your garden.
The potential pests in your yard could be ground squirrels, moles, pocket gophers or voles. You also mentioned that you have had pocket gophers in the past and wondered which of these critters are nocturnal.
All members of the squirrel family except flying squirrels are diurnal – which means they're active primarily during the day. Moles are not nocturnal. This misconception is probably the result of people looking out their window in the morning and seeing fresh mole hills. In fact, moles are not necessarily more or less active at any time during the day or night. They are more active during quiet periods, such as early morning or late in the evening. Pocket gophers are active throughout the day with periods of rest. Voles can be nocturnal or diurnal depending on the species.
The best way to determine what type of pest you have is by the damage you see.
- Ground Squirrels: The key identifier for these rodents is an exposed tunnel entrance with discarded dirt surrounding the entrance of the tunnel. You can see right into a ground squirrel burrow, unlike that of moles or pocket gophers.
- Moles: If you have a mole, you will see mounds of dirt and/or surface tunnels. Dirt mounds (look like piles or "puffs" of dirt shaped like a volcano) and surface tunnels (look like the veins on the back of your hand). Not all moles will have both surface tunnels and dirt mounds. If you see one or the other (or both), you have a mole.
- Pocket Gophers: Damage done by pocket gophers is similar to moles, but there is a major difference. Dirt mounds are crescent-shaped (like a "C") with a "dirt plug" on one side of the mound.
- Voles: Voles typically “piggy back” on the damage done by moles and tend to travel in mole tunnels and often are the cause of damage to roots, bulbs, and tubers within.
UC IPM Pest Notes (via free download) provide specific guidance on identification of these garden pests as well as controls. Here are the links to the appropriate Pest Notes:
Ground Squirrels:
http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7438.html
Moles:
http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn74115.html
Pocket Gophers:
http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7433.html
Voles:
http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7439.html
Good luck on your on successful controls. You have many fellow gardeners who feel your pain.
Please do not hesitate to contact us if you have additional questions.
Help Desk of the UC Master Gardener Program of Contra Costa County (SLH)
Note: The UC Master Gardeners Program of Contra Costa's Help Desk is available year-round to answer your gardening questions. Except for a few holidays, we're open every week, Monday through Thursday for walk-ins from 9:00 am to Noon at 75 Santa Barbara Road, 2d Floor, Pleasant Hill, CA 94523. We can also be reached via telephone: (925) 646-6586, email: ccmg@ucanr.edu, or on the web at http://ccmg.ucanr.edu/Ask_Us/ MGCC Blogs can be found at http://ccmg.ucanr.edu/HortCoCo/ You can also subscribe to the Blog (//ucanr.edu/blogs/CCMGBlog/).
Experts Converge in March to Discuss Human-Wildlife Conflict Resolution
Wildlife and people have been in the news lately. Perhaps you've heard of coyotes wandering in your neighborhood. You might have also read about how you shouldn't feed wildlife. Did you know they are connected? It's a problem when people feed coyotes either intentionally or unintentionally through uncovered garbage and outdoor pet food. Available food may encourage coyotes to associate closely with humans and to lose their natural fear of us. These interactions will be discussed during a special symposium on urban coyotes at the 27th Vertebrate Pest Conference.
The Vertebrate Pest Conference is held every two years, mostly in California. This year, the meeting will be Monday through Thursday, March 7to 10 in Newport Beach. Meetings are held in cooperation with the Pesticide Applicators Professional Association (PAPA). The leading authorities with vertebrate management expertise from around the world congregate to present the latest research and extension information. Are you an animal control official, wildlife manager, agricultural producer, pest control adviser, consultant, educator, researcher, or natural resource manager? Then this meeting is for you. California Department of Pesticide Regulation and California Department of Public Health continuing education units are available for participants.
Special symposia include bird management, wild pig management, and urban coyotes. In Cooperative Extension Advisor Niamh Quinn's backyard of extremely urban Southern California, these coyote-human conflicts occur. With over 3 million people in Orange County, 8 state parks and beaches, countless city parks and 19 county parks and wilderness areas, conflicts with urban coyotes are bound to happen. Managing coyotes includes managing people's behavior too.
Vole Damage in Citrus Revisited
Since the first publication of this article on vole damage in citrus, a recent field observation regarding vole activity is worth noting. Voles prefer a situation where there is cover and shelter generally from weed or grass. In some orchards established in the last few years a plastic strip has been installed along the tree row for weed management (Fig 1). These strips appear to be offering a sheltered environment for vole activity in some cases (Fig 2). Recent observations in two such installations, one a block planted in 2013 and the other an eight year old planting exhibited significant vole activity. The young orchard at this point does not exhibit obvious tree damage although active tunneling is apparent (Fig 3). In the older orchard feeding damage to the trunks is very obvious (Fig 4).
Meadow Mice (Voles) can cause serious damage in a citrus orchard resulting in partial or complete girdling of a tree (Fig 5). Trees often exhibit damage to the bark of the tree from the soil line up 6-8 inches (Fig. 6 ). On close inspection, an open hole 1-1.5 inches in diameter may be found at the base of the tree (Fig 7).
Five species belonging to the genus Microtus are found in California, two of which “Microtus californicus” and “M.montanus” are reported to cause damage. Damage has been reported in permanent pasture, alfalfa, hay, artichokes, Brussels sprouts, carrots, cauliflower, potatoes, sugar beets, tomatoes, grains, nursery stock and the bark of apple, avocado, citrus, cherry and olive trees.
Microtus are often found where there is grass cover. They generally do not invade cultivated crops until the crop is tall enough to provide food and shelter. Meadow mice are active all year round. They forage at any time during the day or night but are chiefly nocturnal. They are usually found in colonies marked by numerous 2-- inch wide surface runways though matted grass. Small brownish fecal pellets and short pieces of grass stems along the runways are evidence of activity. The burrows consist of extensive underground tunnels, nest chambers and storage chambers. Home range is typically small, less than a 60 foot radius in the case of “M.californicus”. All meadow mice swim well. Therefore, irrigation ditches will not serve as effective barriers against meadow mice movement into fields. Meadow mice may forage beyond the sheltered runways. Food consists of tubers, roots, seeds, grain, and succulent stems and leaves.
Females breed at 4 to 6 weeks of age with litter size of “M.californicus” averaging around 4. Under natural conditions a female Microtus may produce from 5 to 10 litters a year. The major breeding season corresponds with the season of forage growth. Microtus populations build up to a peak every 3 to 4 years, followed by a rapid decline during the next breeding season. The exact causes of the cycle of buildup and decline are not known, though disease, food shortages, physiological stress from overcrowding, and other factors may be involved. It is assumed that in cultivated areas Microtus populations are permanently based in favorable habitat such as roadsides, canal banks or adjacent noncultivated land. Invasion of cultivated cropland occurs when the population builds up or when the wild habitat becomes unfavorable. Coyotes, badgers, weasels, snakes, hawks, owls, herons and gulls are among the principal predators. It is believed that predators are not able to prevent or control a population eruption because of the birth rate of the fast breeding Microtus population. Meadow mice are classified as nongame mammals by the California Fish and Game Code. Nongame mammals, which are found to be injuring growing crops may be taken at any time or in any manner by the owner/management. The most effective management options in an orchard situation are a reduction in ground cover and the use of toxic baits. Meadow mice are cover dependent. In situations where cover removal is not possible or is insufficient to solve the problem, the next best option is the use of toxic baits. Many bait carriers are used (e.g., oat groats, wheat bait). Baits: Crimped oat groats are the most satisfactory bait although crimped whole oats are used (e.g., oat groats, wheat grains, pelletized formulations, etc., but crimped oat groats have typically been most effective). The primary toxicants used for meadow mouse control include zinc phosphide, diphacinone, and chlorophacinone. Directions for management including baiting can be obtained by contacting the Agricultural Commissioner's Office. * Portions taken from J.P.Clark Vertebrate Pest Control
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Vole damage in citrus
Recently a six-year old W. Murcott orchard was evaluated for causes of tree decline. A high percentage of the trees exhibited damage to the bark of the tree generally from the soil line up 6-8 inches. (Fig.2) In some instances the tree had been almost totally girdled. On close inspection of the trunk, an open hole 4-5 inches in diameter was found at the base of the tree. (Fig.3)
Microtus are often found where there is grass cover. They generally do not invade cultivated crops until the crop is tall enough to provide food and shelter. Meadow mice are active all year round. They forage at any time during the day or night but are chiefly nocturnal. They are usually found in colonies marked by numerous -2-- inch wide surface runways though matted grass. Small piles of brownish feces and short pieces of grass stems along the runways are evidence of activity. The burrows consist of extensive underground tunnels, nest chambers and storage chambers. Home range is typically small, less than a 60 foot radius in the case of “M.californicus”. All meadow mice swim well. Therefore, irrigation ditches will not serve as effective barriers against meadow mice movement into fields. Meadow mice may forage beyond the sheltered runways. Food consists of tubers, roots, seeds, grain, and succulent stems and leaves.
Females breed at 4 to 6 weeks of age with liter size of “M.californicus” averaging around 4. Under natural conditions a female Microtus may produce from 5 to 10 litters a year. The major breeding season corresponds with the season of forage growth. Microtus populations build up to a peak every 3 to 4 years, followed by a rapid decline during the next breeding season. The exact causes of the cycle of buildup and decline are not known, though disease, food shortages, physiological stress from overcrowding, and other factors may be involved. It is assumed that in cultivated areas Microtus populations are permanently based in favorable habitat such as roadsides, canal banks or adjacent noncultivated land. Invasion of cultivated cropland occurs when the population builds up or when the wild habitat becomes unfavorable. Coyotes, badgers, weasels, snakes, hawks, owls, herons and gulls are among the principal predators. It is believed that predators are not able to prevent or control a population eruption because of the birth rate of the fast breeding Microtus population. Meadow mice are classified as nongame mammals by the California Fish and Game Code. Nongame mammals, which are found to be injuring growing crops may be taken at any time or in any manner by the owner. Management: The most effective management options in an orchard situation are a reduction in ground cover and the use of toxic baits. Meadow mice are cover dependent. If cover is the management of choice - typically weed or grass, the cover can be removed from around the base of a tree, this often solves meadow mice problems. In situations where cover removal is not possible or is insufficient to solve the problem, the next best option is the use of toxic baits. Many bait carriers are used (e.g., oat groats, wheat bait). Baits: Crimped oat groats is the most satisfactory bait although crimped whole oats are used (e.g., oat groats, wheat grains, pelletized formulations, etc., but crimped oat groats have typically been most effective). The primary toxicants used for meadow mouse control include zinc phosphide, diphacinone, and chlorophacinone. Directions for management including baiting can be obtained by contacting the Agricultural Commissioner’s Office.
* Portions taken from J.P.Clark Vertebrate Pest Control
Entrance to burrow (Fig. 2)
Vole (Fig. 3)